1. Field of the Invention
The present invention relates to a method for fabrication of a semiconductor sensor including a gauge resistor.
2. Related Art
JP-U-4-25256 discloses a semiconductor pressure sensor including a bridge circuit formed by a plurality of gauge resistors on a substrate. This publication teaches a technique which makes an offset voltage of the bridge circuit zero. In order to make the offset voltage zero, transcription of the gauge can be improved by arranging the gauge resistors and dummy patterns in a line on the substrate. However, the disclosed technique makes the offset voltage zero only in the single semiconductor chip to which the technique is applied. With the described technique, it is impossible to remove the influence of photo masks used for patterning the gauge resistors (an impurity diffusion layer). That is, the described technique can decrease the non-uniformity of resistance caused by photo or diffusion processes. In contrast, it is impossible to decrease the non-uniformity of width of a gauge mask used for patterning the gauge reisistors (a kind of photo mask).